GENETIC-VARIABILITY IN DEMERSAL FISHES - DEPTH DISTRIBUTION VERSUS PHYLOGENETIC CONSTRAINTS

Microevolutionary processes in deep sea environment has been the most difficult to deal with. There are hypothesis that consider those envir onment as paradigm of stability. Another hypothesis postulate periodic als disturbations where the species reacts according with the plastici ty of the genetic information and restricting phylogenetics. In this c ontext genetic variability has been studied in three species that inha bit deep sea of the Chilean coast, two macrourids and a morid: Macrour us holotrachys Caeloiynchus fasciatus and Antimora rostrata. 29 loci w ere studied and three of them are polymorphic coincident for the three species. The genetic variability is very low, 0.03; 0.026 and 0.05 re spectively. Apparently these values fit with Smith and Fujio hypothesi s that relates low variability and habitat generalist. On the other ha nd every species develops different behaviour with different capacitie s to explore the environment. The Gadiform group shows as a characteri stics low variability (Smith and Fujio, 1982). In comparing against ot her groups the low variability could be the result of phylogenetic con strain in the group.